كَفَّ غَضَبَهُ uses كَفَّ meaning to hold back or restrain. Anger may arise involuntarily, but a person can still prevent it from becoming abuse, verbal injury, or an unjust decision. That is practical self-control.
Example 1: During disagreement, take a suitable pause before responding harshly.
Example 2: A parent, teacher, or supervisor should avoid humiliation and unfair treatment even when displeased.
Example 3: Defend legitimate rights using evidence and respectful language rather than rage.
Restraining anger is not a command never to express a grievance. It is a safeguard against wrongful responses.